<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>

</head>

<body>
  <div id="app">
    <div :class="[a, 'box2', 1==1&&'a']">111</div>
    <div :class="{
      a: 1==1,
      b: true,
      active: 1<2,
      c: false
    }">222</div>
    <div :class="[a, 'box2', {
      a: 1==1,
      b: true,
      active: 1<2,
      c: false
    }]">33</div>
  </div>
  <script src="./vue.global.js"></script>
  <script>
    const { createApp } = Vue;
    const app = createApp({
      data() {
        return {
          a: 'box'
        }
      }
    })
    app.mount('#app')
  </script>
</body>

</html>